I cannot say I obsess over a few GPT for it to matter. Gold is already more then plentiful--there is a reason why players say diplo is the easiest or the "sneak in a win when about to lose" victory. I build a lot of convenience roads (roads in areas for easier travel, not for city connection), amass tons of military, and I still have more gold than I need. In BNW I mainly stick to internal trade-routes since the gold from trade is overkill.
I guess my point here is I cannot simply think of something as "broken" when it is literally a handful of gpt in a game where you rake in hundreds of gold per turn. If the burst of influence isn't worth the gpt, then just don't build the road.